Method and system for substrate thinning

ABSTRACT

A method and a system for thinning a substrate are provided. The method includes at least the following steps. A liquid seal is provided at an interface between a chuck and a substrate disposed on the chuck. The substrate is thinned during the liquid seal is provided.

BACKGROUND

Semiconductor devices are used in a variety of electronic applications,such as personal computers, cell phones, digital cameras, and otherelectronic devices. As the demand for shrinking electronic devices hasgrown, a need for smaller and more creative packaging techniques ofsemiconductor dies has emerged. Thus, packages such as wafer levelpackaging (WLP) have begun to be developed. For example, semiconductordevices are fabricated by sequentially forming various material layersand structures over previously formed layers and structures. Due tovarying coefficients of thermal expansion (CTEs) of different materials,thermal issues during the fabrication process may lead to warpage of thesemiconductor devices.

Moreover, in the manufacturing of semiconductor devices, a grindingprocess is performed to reduce the thickness of the structures. As thefinal thickness of the semiconductor device shrinks, damage caused bythe grinding process becomes a bigger concern. For example, in aconventional grinding process, vacuum leakage may occur at the edge ofthe structure due to warpage. In addition, a grinding process may resultin a grinded surface having unacceptable total thickness variation(TTV). Moreover, a structure to be thinned having a smaller thickness iswarped at its periphery and becomes easily cracked during the grinding.Furthermore, over-grinding may occur and cause damage to a portion ofthe structure, thereby leading to yield loss. Therefore, there is a needfor an improved method and system for thinning semiconductor devices.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1A to FIG. 1H are schematic cross-sectional views of various stagesin a manufacturing method of a semiconductor device according to someexemplary embodiments of the disclosure.

FIG. 2 is a schematic perspective view of the structure depicted in FIG.1B or FIG. 1E according to some exemplary embodiments of the disclosure.

FIG. 3A to FIG. 3G are schematic cross-sectional views of various stagesin a manufacturing method for thinning a substrate according to someexemplary embodiments of the disclosure.

FIG. 4 is a schematic top view of the dashed box A depicted in FIG. 3Baccording to some exemplary embodiments of the disclosure.

FIG. 5 and FIG. 6 are schematic cross-sectional views illustrating aliquid supply of a system for thinning a substrate according to someexemplary embodiments of the disclosure.

FIG. 7 is a schematic perspective view of the dashed box B depicted inFIG. 3C according to some exemplary embodiments of the disclosure.

FIG. 8 is an enlarged, schematic cross-sectional view of the dashed boxC depicted in FIG. 3C according to some exemplary embodiments of thedisclosure.

FIG. 9 is a schematic bottom view illustrating a thinning deviceaccording to some exemplary embodiments of the disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components, values, operations, materials,arrangements, or the like, are described below to simplify thedisclosure. These are, of course, merely examples and are not intendedto be limiting. Other components, values, operations, materials,arrangements, or the like, are contemplated. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the disclosure may repeat reference numerals and/or letters inthe various examples. This repetition is for the purpose of simplicityand clarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

In addition, terms, such as “first,” “second,” and the like, may be usedherein for ease of description to describe similar or differentelement(s) or feature(s) as illustrated in the figures, and may be usedinterchangeably depending on the order of the presence or the contextsof the description.

FIG. 1A to FIG. 1H are schematic cross-sectional views of various stagesin a manufacturing method of a semiconductor device according to someexemplary embodiments of the disclosure, and FIG. 2 is a schematicperspective view of the structure depicted in FIG. 1B or FIG. 1Eaccording to some exemplary embodiments of the disclosure. Referring toFIG. 1A, a plurality of first dies 110 are disposed on a substratecarrier 50. In some embodiments, the substrate carrier 50 is a glasscarrier, a ceramic carrier, or the like. In some other embodiments, thesubstrate carrier 50 is a blank silicon wafer that has no integratedcircuits formed thereon. The first dies 110 may be adhered on thesubstrate carrier 50 through a release layer 52. The material of therelease layer 52 may be any material suitable for bonding and de-bondingthe substrate carrier 50 from the structure subsequently formed thereon.For example, the release layer 52 includes a layer oflight-to-heat-conversion (LTHC) release coating and a layer ofassociated adhesive (e.g., a ultra-violet curable adhesive or a heatcurable adhesive layer), or the like.

The first dies 110 may be known-good-dies that are sawed from a devicewafer and are selected to be bonded onto the substrate carrier 50. Thefirst dies 110 may be spaced apart from each other on the substratecarrier 50. In some embodiments, the first dies 110 are dies thatinclude active devices (e.g., transistors; not shown). In someembodiments, each of the first dies 110 may include conductive posts 112and a protection layer 114 covering the conductive posts 112. At least aportion of the conductive posts 112 are exposed by the protection layer114 for formation of fan-out connections. The conductive posts 112 maybe pre-formed in the first dies 110. In some embodiments, the conductiveposts 112 include a first subset and a second subset arranged aside thefirst subset. The design of different layout densities may lead to asize difference between the first and second subset of the conductiveposts 112. For example, the size (e.g., width or diameter, etc.) of eachconductive post 112 belonging to the first subset is smaller than thatof the second subset of the conductive posts 112. The layout density ofthe first subset of the conductive posts 112 may be greater than thesecond subset of the conductive posts 112. For example, the conductiveposts 112 belonging to the first subset have a tighter spacingtherebetween for further fine-pitch electrical connection (e.g.,connection of second die 150 as shown in FIG. 1D). The conductive posts112 belonging to the second subset may have a loosely arrangement forfurther coarse-pitch electrical connection (e.g., connection ofconductive connector 140 as shown in FIG. 1D). In some embodiments, thefirst dies 110 are arranged in a parallel manner, the first subset ofthe conductive posts 112 of one of the two adjacent first die 110 isdisposed at the side of the first die 110 close to the other one of thetwo adjacent first die 110, and the second subset of the conductiveposts 112 of the one of the two adjacent first die 110 is disposed atthe opposite side of the first die 110 away from the other one of thetwo adjacent first die 110. In some alternative embodiments, the firstsubset and the second subset of the conductive posts 112 are formed withthe same size and/or the same layout density according to the designrequirements. For example, the conductive posts 112 includes copperposts, copper alloy posts, or other suitable metal posts, which areelectrically coupled to the active devices in the first dies 110. Theprotection layer 114 may be made of polybenzoxazole (PBO), polyimide(PI), any suitable polymers or inorganic materials. It should beappreciated that the illustration of the first dies 110 and othercomponents throughout all figures is schematic and is not in scale.

Referring to FIG. 1B and FIG. 2, a first insulating material 120′ isformed over the substrate carrier 50. For example, the first insulatingmaterial 120′ is filled into the space between and over the first dies110 to form a first structure S1. In some embodiments, the firststructure S1 may be viewed as a reconstituted wafer as shown in FIG. 2.In some embodiments, the first insulating material 120′ is a moldingcompound formed by a molding process followed by a curing process. Forexample, the first insulating material 120′ is over-molded toencapsulate the first dies 110. The conductive posts 112 and theprotection layer 114 of the die 110 are not revealed and well protectedby the first insulating material 120′. The first insulating material120′ may include epoxy resin, or other suitable dielectric materials. Insome embodiments, thermal treatment (e.g., a curing process) to thefirst insulating material 120′ results in bowing and warpage of thefirst structure S1.

Referring to FIG. 1C, a thinning process is performed to remove aportion of the first insulating material 120′ to form the firstinsulating encapsulation 120. For example, after forming the firstinsulating material 120′, the first structure S1 is transferred to thenext station for thinning. A thickness of the first insulating material120′ may be reduced to reveal at least a portion of the conductive posts112 of the first dies 110. In some embodiments, the first insulatingmaterial 120′ is thinned by a mechanical grinding process and/or achemical mechanical polishing (CMP) process. In some embodiments, thefirst insulating material 120′ is thinned until the top surfaces of theconductive posts 112 and the top surface of the protection layer 114 areexposed. In some embodiments, during the thinning process, not only thefirst insulating material 120′, but also portions of the conductiveposts 112 and/or the protection layer 114 are slightly thinned. Afterthinning the first structure S1, the top surface 120 a of the firstinsulating encapsulation 120 may be substantially coplanar with the topsurfaces 110 a of the first dies 110. After the conductive posts 112 areexposed, fan-out connections may be formed to electrically connect theconductive posts 112. For example, fan-out connections are theelectrical connections extended to an area larger than the area of thefirst dies 110. The detailed description of a thinning process will bedescribed later accompanying with FIGS. 3A to 3G.

Referring to FIG. 1D, a first redistribution structure 130 and aconductive connector 140 are formed on the top surface 120 a of thefirst insulating encapsulation 120 and the top surfaces 110 a of thefirst dies 110 to electrically couple to the first dies 110. A seconddie 150 is then mounted on the first redistribution structure 130. Forexample, the conductive connector 140 may be formed aside the second die150. The first redistribution structure 130 may include a firstdielectric layer 132 and a first patterned conductive layer 134 stackedone another. For example, a dielectric material (e.g., PBO, PI,benzocyclobutene (BCB), or other material that is electricallyinsulating) is formed over the top surface 120 a of the first insulatingencapsulation 120 and the top surfaces 110 a of the first dies 110 usingany suitable method, such as a spin-on coating process, a depositionprocess, or the like. Next, a portion of the dielectric material isremoved to form the first dielectric layer 132 having a plurality ofopenings (not marked). The openings of the first dielectric layer 132expose at least a portion of the conductive posts 112 of the dies 110.Next, a conductive material (e.g., copper, copper alloy, aluminum,aluminum alloy, or combinations thereof) is deposited in the openings ofthe first dielectric layer 132 and over the first dielectric layer 132.Subsequently, the conductive material is patterned to form the firstpatterned conductive layer 134 using lithography, or other suitabletechniques. The portion of the first patterned conductive layer 134formed in the openings of the first dielectric layer 132 is in physicalcontact with the conductive posts 112 of the first dies 110. In someembodiments, the abovementioned steps may be performed multiple times toobtain a multi-layered redistribution structure as required by thecircuit design. That is, the numbers of the first dielectric layer 132and the first patterned conductive layer 134 can be selected based ondemand and are not limited in the disclosure.

After forming the first redistribution structure 130, the conductiveconnector 140 may be formed on the first redistribution structure 130.For example, the conductive connectors 140 may be formed by forming amask pattern (not shown) having openings, where the mask pattern coversa portion of the first redistribution structure 130 and exposes anotherportion of the first patterned conductive layer 134 with the openings;forming a conductive material to fill the openings so as to form theconductive connector 140 by electroplating or deposition; and thenremoving the mask pattern. In certain embodiments, the conductiveconnectors 140 are through integrated fan-out (InFO) vias. After formingthe conductive connectors 140, the second die 150 is provided andmounted on the first redistribution structure 130 using, for example, aflip-chip technique and/or surface mount techniques. The number of thesecond die 150 can be selected based on demand, and is not limited inthe disclosure. For example, the second die 150 includes a semiconductorsubstrate 152, one or more through silicon vias (TSVs) 154 embedded inthe semiconductor substrate 152, and connecting pads 156 disposed on thetop surface 150 a of the semiconductor substrate 152. In one embodiment,the semiconductor substrate 152 may be a silicon substrate includingactive components (e.g., diodes, transistors, or the like) and passivecomponents (e.g., resistors, capacitors, inductors or the like) formedtherein. In some embodiments, each of the TSVs 154 has one end connectedto one of the connecting pads 156, and the opposite ends of the TSVs 154are embedded in the semiconductor substrate 152.

In some embodiments, the second die 150 is bonded to the firstredistribution structure 130 by forming a plurality of conductive joints160 between the second die 150 and the first redistribution structure130. For example, the conductive joints 160 are made of soldermaterials. The second die 150 is electrically communicated to the firstdies 110 through the first redistribution structure 130. In someembodiments, an underfill material UF is formed between the top surface150 a of the second die 150 and the first redistribution structure 130and dispensed around the conductive joints 160. For example, theunderfill material UF is disposed on the first redistribution structure130 and laterally wraps the conductive joints 160 to provide structuralsupport and protection to the conductive joints 160. In someembodiments, the underfill material UF covers the top surface 150 a andthe sidewalls of the second die 150, and exposes the bottom surface ofthe second die 150, as shown in FIG. 1D.

Referring to FIG. 1E and FIG. 2, after mounting the second die 150, asecond insulating material 170′ is formed over the first redistributionstructure 130. For example, the second insulating material 170′ at leastfills the gaps among the conductive connectors 140, the second die 150,and the underfill material UF. In some embodiments, the conductiveconnectors 140, the second die 150 and the underfill material UF areencapsulated in the second insulating material 170′ to form a secondstructure S2 as shown in FIG. 2. A material and a forming process of thesecond insulating material 170′ may be the same as or similar with thatof the first insulating material 120′, and the detailed descriptions areomitted for brevity. In some alternative embodiments, the underfillmaterial UF is omitted, and the second insulating material 170′ isformed using a molded underfill (MUF) process. For example, a MUFmaterial is used as the second insulating material 170′, which canprovide both the underfill beneath the second die 150 and surroundingthe conductive connectors 140, and a protective over-molded secondstructure S2. In some embodiments, after forming the second insulatingmaterial 170′, due to varying coefficient of thermal expansions ofdifferent materials, the second structure S2 may bow (or warp) upward atthe edges (not shown in FIG. 1E).

Referring to FIG. 1F, a thinning process is performed on the secondstructure S2 to remove a portion of the second insulating material 170′so as to form a second insulating encapsulation 170. The detaileddescription of a thinning process will be described later accompanyingwith FIGS. 3A to 3G. In some embodiments, the second insulating material170′ is thinned until the top surfaces 140 a of the conductiveconductors 140 are exposed. In some embodiments, during the thinningprocess, not only the second insulating material 120′, but also portionsof the conductive conductors 140 and/or the semiconductor substrate 152of the second die 150 are slightly thinned. For example, after thinningthe second structure S2, a portion of the semiconductor substrate 152 isremoved, and the ends of the TSVs 154 which were embedded in thesemiconductor substrate 152 may be accessibly reveled by the bottomsurface 150 b of the second die 150. In some embodiments, the pitchbetween the two adjacent TSVs 154 of the second die 150 may be smallerthan the pitch between the two adjacent conductive conductors 140. Thesize (e.g., width or diameter, etc.) of each conductive conductor 140may be greater than that of each TSVs 154 of the second die 150. In someembodiments, after performing the thinning process, a top surface 170 aof the second insulating encapsulation 170 is substantially coplanarwith the bottom surface 150 b of the second die 150 and the top surfaces140 a of the conductive conductors 140.

Referring to FIG. 1G, a second redistribution structure 180 andconductive terminals 190 are formed over the top surface 170 a of thesecond insulating encapsulation 170, the bottom surface 150 b of thesecond die 150 and the top surfaces 140 a of the conductive conductors140. The second redistribution structure 180 may include a seconddielectric layer 182 and a second patterned conductive layer 184 stackedone another. The numbers of the second dielectric layer 182 and thesecond patterned conductive layer 184 are not limited in thisdisclosure. A material and a forming process of the secondredistribution structure 180 may be similar with that of the firstredistribution structure 130, and the detailed descriptions aresimplified. For example, the second dielectric layer 182 including aplurality of openings (not marked) is formed on the top surface 170 a ofthe second insulating encapsulation 170, the bottom surface 150 b of thesecond die 150 and the top surfaces 140 a of the conductive conductors140. The openings of the second dielectric layer 182 may expose at leasta portion of the conductive conductors 140 and/or at least a portion ofthe TSVs 154 of the second die 150. Next, the second patternedconductive layer 184 is formed in the openings of the second dielectriclayer 182 and formed on the second dielectric layer 182. In someembodiments, one or more layers of dielectric materials may berepresented collectively as the second dielectric layer 182, andconductive features (e.g. conductive lines, conductive pads, and/orconductive vias) are collectively represented as the second patternedconductive layer 184. In some embodiments, a plurality of conductivepads (not marked) may be formed on some of the top surface of thetopmost layer of the second patterned conductive layer 184 forelectrically connecting with the later-formed components. For example,the conductive pads include under-ball metallurgy (UBM) patterns for aball mounting process.

After forming the second redistribution structure 180, the conductiveterminals 190 are formed thereon for external electrical connection. Insome embodiments, the conductive terminals 190 are disposed on thesecond patterned conductive layer 184 of the second redistributionstructure 180 using a ball placement process, a plating process, orother suitable processes. The conductive terminals 190 include solderballs, ball grid array (BGA) balls, or other terminals, but is notlimited thereto. Other possible forms and shapes of the conductiveterminals 190 may be used according to design requirements. In someembodiments, a soldering process and a reflow process may be optionallyperformed for enhancement of adhesion between the conductive terminals190 and the second redistribution structure 180. After forming theconductive terminals 190, the substrate carrier 50 may be removed toexpose the first dies 110 and the first insulating encapsulation 120.For example, the substrate carrier 50 is detached through a de-bondingprocess. In some embodiments, the external energy (e.g., UV laser,visible light or heat) is applied to the release layer 52 so that thecarrier 50 can be separated from the first dies 110 and the firstinsulating encapsulation 120.

Referring to FIG. 1H, after removing the substrate carrier 50, asingulation (or dicing) process may be performed along the cutting lines(not shown) to form a plurality of individual and separatedsemiconductor devices 10. The singulation process may include mechanicalsawing or laser cutting.

FIG. 3A to FIG. 3G are schematic cross-sectional views of various stagesin a manufacturing method for thinning a substrate according to someexemplary embodiments of the disclosure, and FIG. 4 is a schematic topview of the dashed box A depicted in FIG. 3B according to some exemplaryembodiments of the disclosure. A method for thinning a substrate isprovided in accordance with various embodiments. It is appreciated thatthe formation of the semiconductor device 10 described in FIG. 1A toFIG. 1H are used as examples. The thinning method in accordance withembodiments herein may be used for thinning other types of objects atvarious formation stages, for example, backside grinding of siliconwafers, thinning of semiconductor packages at the wafer scale or chipscale, or the like. It should be also noted that a thinning process ofthe first structure S1 shown in FIG. 1B is described in the followingexemplary embodiments. The second structure S2 shown in FIG. 1E can bethinned by the similar thinning steps.

Referring to FIG. 3A to FIG. 3B and FIG. 4 as well as FIG. 1B and FIG.2, after the first structure S1 is formed, the first structure S1 may betransported to another working stage using a wafer transfer system 40.For example, the wafer transfer system 40 includes a holding device 42(e.g., robot arm). In some embodiments, vacuum lines (not shown) areprovided in the holding device 42, so that the holding device 42 canhold the first structure S1 thereon through vacuum-absorption. The firststructure S1 can be secured and transported by the wafer transfer system40 in other suitable means which can stably hold the structure thereon.The first structure S1 includes a front side FS and a backside BSopposite to the FS. For example, the first insulating material 120′ ofthe first structure S1 shown in FIG. 1B is at the front side FS, and thecarrier 50 is at the backside BS. In some embodiments, the wafertransfer system 40 is first positioned to the first structure S1 on thestage for transporting as shown in FIG. 3A. Next, the first structure S1is picked up from the stage. For example, the front side FS of the firststructure S1 is stably held by the holding device 42, and then the firststructure S1 is transported to the next station for thinning as shown inFIG. 3B.

Continue to FIG. 3B and FIG. 4, a system 20 for thinning includes asupporting assembly 200. The supporting assembly 200 includes a chuck210 and a first liquid supply unit 220 assembled on the chuck 210. Thechuck 210 including a carrying surface CS is used to support and securethe first structure S1 placed thereon. The first liquid supply unit 220including a first discharging conduit 222 is used to supply liquid tothe first structure S1 during processing. In some embodiments, the firstliquid supply unit 220 is detachably assembled onto the outer peripheryof the chuck 210, thereby allowing convenient replacement andmaintenance works. In some alternative embodiments, the first liquidsupply unit 220 and the chuck 210 are integrally-formed. In someembodiments, the chuck 210 includes a base 212, a frame portion 214, anda sucking portion 216. The frame portion 214 and the sucking portion 216are disposed on the base 212. For example, the base 212 is provided atthe bottom of the chuck 210, and the frame portion 214 and the suckingportion 216 are provided at the top of the chuck 210. In someembodiments, the top surface area of the chuck 210 is less than thebottom surface area of the chuck 210. In some alternative embodiments,the top surface area of the chuck 210 is substantially equal to thebottom surface area of the chuck 210. In some embodiments, the base 212and the frame portion 214 are integrally-formed, and the frame portion214 is an annular partition on the base 212. The sucking portion 216 maybe in disc form and secured inside the frame portion 214. The suckingportion 216 may be in other forms depending on the design requirements.

The sucking portion 216 of the chuck 210 may be made of a porousmaterial (e.g., polymer, ceramic, or the like) or other suitablematerials. In some embodiments, a surface of the sucking portion 216exposed by the frame portion 214 and the base 212 is adapted to carrythe first structure S1, so the surface of the sucking portion 216 isviewed as the carrying surface CS of the chuck 210. In some alternativeembodiments in which the object to be thinned has a relatively largersize, the surface of the sucking portion 216 and the surface of theframe portion 214 surrounding the surface of the sucking portion 216 areviewed as the carrying surface CS of the chuck 210. In some embodiments,the sucking portion 216 includes an air passage 216 a. For example, thesucking portion 216 may be connected to a vacuum system (not shown).After the first structure S1 is placed on the chuck 210 and when thechuck 210 is in use, air can be sucked out from inside the suckingportion 216 through the air passage 216 a, so that the first structureS1 placed on the carrying surface CS of the chuck 210 can be sucked andsecured. The chuck 210 may be equipped with any suitable securingmechanism for holding the structure placed thereon. It should be notedthat the vacuum system of the chuck 210 serves merely as one ofexemplary means to secure the first structure S1, and other suitablemeans (e.g., applying mechanical force) of securing the first structureS1 are considered within the scope of other embodiments. It isappreciated that the illustration of the chuck 210 and other componentsthroughout the figures are schematic and some components are omitted.For example, the chuck 210 may be provided with a rotation mechanism(e.g., shaft, motor, controller, or the like; not shown), therebyallowing rotation around the center axis of the sucking portion 216 asthe center.

In some embodiments, the first liquid supply unit 220 may be engagedwith the base 212 and/or the frame portion 214 of the chuck 210. Forexample, the first liquid supply unit 220 is made of non-wettingmaterials (e.g., plastic, rubber, or the like), or other suitablematerials. In some embodiments, the first liquid supply unit 220 is anannular-shaped component mounted on the periphery of the chuck 210. Forexample, the first liquid supply unit 220 is attached on the peripheryof the base 212 and is concentric with the frame portion 214. The firstliquid supply unit 220 may be a rim having other suitable shapes (e.g.,rectangular, polygon, or the like) fitting closely to the chuck 210. Thefirst discharging conduit 222 of the first liquid supply unit 220 may bedisposed surrounding the frame portion 214 of the chuck 210 andobliquely towards the carrying surface CS. For example, the firstdischarging conduit 222 is disposed at an inclined angle to the annularsidewall of the frame portion 214. In some embodiments, a plane PL wherethe carrying surface CS is located intersected with an inclined axis AX1of the first discharging conduit 222 forms an included angle θ1. Theincluded angle θ1 may be in a range of about 10 degrees to about 80degrees. In some alternative embodiments, the plane PL is substantiallyparallel to the axis AX1 of the first discharging conduit 222.

The first discharging conduit 222 is adapted to convey a liquiddischarging from an outlet 222 a of the first discharging conduit 222towards the carrying surface CS of the chuck 210. The outer diameter (orwidth) of the outlet 222 a of the first discharging conduit 222 is in arange of about 1 mm to about 4 mm. In some embodiments, the first liquidsupply unit 220 includes a plurality of first discharging conduits 222,and each of the first discharging conduits 222 has the outlet 222 a(i.e. opening). The outlets 222 a of the first discharging conduits 222may be evenly distributed around the frame portion 214 of the chuck 210.For example, the outlets 222 a of the first discharging conduits 222 areset in at substantially equal intervals IN as a means to present a moreuniform liquid supply. In some alternative embodiments, the adjacentoutlets 222 a are spaced at different intervals IN. In some embodiments,the outlets 222 a of the first discharging conduits 222 arecircumferentially distributed surrounding the carrying surface CS of thechuck 210 as shown in FIG. 4. It should be noted that the round-shapedoutlet 222 a illustrated in FIG. 4 merely serves as an example, othershaped outlet (e.g., square-shaped, oval-shaped, rectangular-shaped, orthe like) of the first discharging conduit 222 may be applied. In someembodiments, a surface 220 a (e.g., where the outlet 222 a is located)of the first liquid supply unit 220 is substantially leveled with thecarrying surface CS of the chuck 210.

In some alternative embodiments, the surface 220 a of the first liquidsupply unit 220 and the carrying surface CS of the chuck 210 are not atthe same level. For example, the surface 220 a of the first liquidsupply unit 220 is slightly higher or lower than the carrying surface CSof the chuck 210 depending on design requirements. In some embodiments,the number of the outlets 222 a (or the first discharging conduits 222)is equal or greater than 16. More or less number of the outlets 222 a(or the first discharging conduits 222) can be configured depending ondesign requirements, which is not limited in the disclosure.

FIG. 5 and FIG. 6 are schematic cross-sectional views illustrating aliquid supply of a system for thinning a substrate according to someexemplary embodiments of the disclosure. Continue to FIG. 3B withreference to FIG. 5 and FIG. 6, the first discharging conduit 222includes a vertical segment 222 b and an inclined segment 222 c incommunication with the vertical segment 222 b. In some embodiments, thefirst liquid supply unit 220 further includes a liquid supply 230 incommunication with the first discharging conduits 222 of the firstliquid supply unit 220. A liquid control system (e.g., pump, valve,controller, or the like; not shown) may be connected to the liquidsupply 230 and/or the chuck 210 and/or the first liquid supply unit 220for the control of the liquid conveying from the liquid supply 230,passing through the chuck 210, and discharging from the outlets 222 a ofthe first liquid supply unit 220. In some embodiments, the liquid supply230 is an external liquid delivery system coupled to the first liquidsupply unit 220.

In some embodiments, the liquid supply 230′ includes a main channel 232a disposed in the center of the chuck 210, and a plurality of branchchannels 232 b in communication with the main channel 232 a andextending across the chuck 210 to connect the vertical segment 222 b ofthe first discharging conduits 222 as shown in FIG. 5. For example, themain channel 232 a of the liquid supply 230 is vertically disposedinside the center of the base 212. The branch channels 232 b connectedto the main channel 232 a are horizontally distributed inside the base212 and laterally penetrate through the base 212. The number of thebranch channels 232 b may correspond to that of the first dischargingconduits 222. The liquid may be conveyed upwardly (as shown by arrows inFIG. 5) through the main channel 232 a and distributed to the branchchannels 232 b; next, the liquid may be delivered from the center to theperiphery of the base 212 of the chuck 210, and then the liquiddischarges out of the chuck 210 and flows into the vertical segments 222b of the first discharging conduits 222. Subsequently, the liquid isdelivered to the inclined segments 222 c and discharges out from theoutlets 222 a.

In some embodiments, the liquid supply 230″ is split into a plurality ofducts 234 disposed inside at the periphery of the base 212 of the chuck210 as shown in FIG. 6. The number of the ducts 234 may correspond tothat of the first discharging conduits 222. Each of the ducts 234 mayinclude a vertical segment 234 a, a horizontal segment 234 b connectedto one of the vertical segments 222 b of the first discharging conduits222, and a turning segment 234 c connected to the vertical segment 234 aand the horizontal segment 234 b. For example, the liquid may beconveyed upwardly (as shown by arrows in FIG. 6) in the vertical segment234 a to the turning segment 234 c then to the horizontal segment 234 b.The liquid subsequently discharges out of the chuck 210 and flows intothe vertical segments 222 b of the first discharging conduits 222.

FIG. 7 is a schematic perspective view of the dashed box B depicted inFIG. 3C according to some exemplary embodiments of the disclosure, andFIG. 8 is an enlarged, schematic cross-sectional view of the dashed boxC depicted in FIG. 3C according to some exemplary embodiments of thedisclosure. Turning to FIG. 3C with reference to FIG. 7 and FIG. 8, thefirst structure S1 is placed on the chuck 210 of the supporting assembly200 by the wafer transfer system 40. For example, the first structure S1is put on the carrying surface CS of the chuck 210. At this step, theholding device 42 of the wafer transfer system 40 still secures thefront side FS of the first structure S1, and the backside BS of thefirst structure S1 faces toward the sucking portion 216 of the chuck 210as shown in FIG. 3C. The air passage 216 a may be covered by the firststructure S1. In some embodiments, the sucking portion 216 of the chuck210 may be partially exposed by the first structure S1 disposed thereon,and the outlets 222 a of the first discharging conduits 222 aredistributed surrounding the first structure S1 as shown in FIG. 7. Insome embodiments, after disposing the first structure S1 on the chuck210, the backside BS of the first structure S1 is partially contact withthe carrying surface CS of the chuck 210. The area of an interface IFbetween the backside BS of the first structure S1 and the carryingsurface CS may be smaller than the area of the backside BS of the firststructure S1. A gap G may be formed between at the edge EG of the firststructure S1 and the carrying surface CS of the chuck 210 due to warpageat the edge EG of the first structure S1 as shown in FIG. 8.

Referring to FIG. 3D, after disposing the first structure S1 on thechuck 210, a liquid seal LS is provided at the interface IF between thechuck 210 and the first structure S1. For example, a first liquid L1 isprovided and laterally flows to the edge EG of the first structure S1 soas to seal the gap G (marked in FIG. 8) between the chuck 210 and thefirst structure S1. In other words, the gap G between the chuck 210 andthe first structure S1 is filled with the first liquid L1 provided bythe first liquid supply unit 220 to seal the interface IF between thefirst structure S1 and the carrying surface CS of the chuck 210. Whenthe first liquid supply unit 220 delivers the first liquid L1, the firstliquid L1 flows upwardly through the first discharging conduits 222 anddischarges from the outlets 222 a on the surface 220 a to the edge EG ofthe first structure S1, so that the first liquid L1 may continuouslyflow on the carrying surface CS so as to provide a seal to the interfaceIF between the first structure S1 and the carrying surface CS. The firstliquid L1 may be water, a liquid having a relatively neutral pH, orother suitable fluids, which not causes damage to the first structureS1. The pressure and velocity of the flowing first liquid L1 providingby the liquid supply 230 may be adjusted by the liquid control system(not shown) based on design requirements.

Referring to FIG. 3E, vacuum suction VS (as shown by dashed arrow) isperformed to the first structure S1 through the chuck 210. The vacuumcauses the first structure S1 to secure firmly onto the carrying surfaceCS of the chuck 210. In some embodiments, the vacuum suction VS isperformed after providing the liquid seal LS. In some alternativeembodiments, the vacuum suction VS is performed after disposing thefirst structure S1 and prior to providing the liquid seal LS. Forexample, the vacuum suction VS is applied in the center region of thesupporting assembly 200 and the first liquid L1 is provided in theperiphery region of the supporting assembly 200. When the vacuum suctionVS is applied, a portion of the first liquid L1 may be drawn by vacuumpressure and may enter the sucking portion 216 and then drain to the airpassage 216 a in the sucking portion 216. In some embodiments, afterapplying the vacuum suction VS and providing the liquid seal LS, thestep of assessing vacuum leakage may be performed by measuring vacuumsuction pressure. For example, if the edge EG of the first structure S1is appropriately sealed by the first liquid L1, a relatively constantsuction pressure can be maintained, thereby ensuring a reliable liquidseal at the edge EG of the first structure S1.

Referring to FIG. 3F, after the vacuum suction VS is applied, theholding device 42 of the wafer transfer system 40 is removed to releasethe first structure S1 so that the front side FS of the first structureS1 is exposed. For example, after the liquid seal LS is provided, thevacuum suction VS is applied and followed by releasing the holdingdevice 42. In some alternative embodiments, when the wafer transfersystem 40 reaches the processing station, the first structure S1 held onthe holding device 42 is placed on the carrying surface CS of the chuck210 and secured by means of the vacuum suction VS, and then the holdingdevice 42 is removed by releasing vacuum-absorption to the front side FSof the first structure S1. During the vacuum suction VS is applied,vacuum leakage may occur at the edge EG of the first structure S1 due towarpage, so the first liquid L1 is provided to seal the edge of thefirst structure S1.

FIG. 9 is a schematic bottom view illustrating a thinning deviceaccording to some exemplary embodiments of the disclosure. Turning toFIG. 3G with reference to FIG. 9, the first structure S1 is thinned by athinning device 300 during the liquid seal LS is provided. In someembodiments, when the first structure S1 is thinned, vacuum suction VSis continuously applied through the chuck 210 so as to secure the firststructure S1. In some embodiments, the thinning device 300 disposedabove the chuck 210 includes a thinning wheel 310 and a second liquidsupply unit 320 surrounded by the thinning wheel 310. The firststructure S1 is machined to have a predetermined thickness by therotation of the thinning wheel 310. For example, the thinning wheel 310includes a plurality of grinding pads 312 circumferentially disposed onthe thinning wheel 310 for grinding or smoothing the first structure S1.The grinding pads 312 can be applied to the front side FS of the firststructure S1 for rough grinding and/or polishing. In some embodiments, asecond liquid L2 is provided downwardly from the second liquid supplyunit 320 of the thinning device 300 to the front side FS of the firststructure S1 when thinning the first structure S1. The thinning device300 may further include a control unit (not shown) coupled to thethinning wheel 310 and the second liquid supply unit 320 for controllingthe action of thinning wheel 310 and the amount of the second liquid L2.During the thinning process, the thinning wheel 310 and the firststructure S1 both rotate. When the first structure S1 is spinning, aportion of the first liquid L1 provided by the first liquid supply unit220 may be thrown away by centrifugal force from the chuck 210.

In some embodiments, the second liquid supply unit 320 includes aplurality of second discharging conduits 323 obliquely disposed towardsthe grinding pads 312 for spraying the second liquid L2 to the firststructure S1. For example, the axes AX2 of the second dischargingconduits 323 intersected with the surface of the front side FS of thefirst structure S1 forms an acute angle θ2. The second liquid supplyunit 320 may include another liquid supply system (not shown) differentfrom the liquid supply 230 of the supporting assembly 200. The secondliquid L2 may be water, a liquid having a relatively neutral pH, orother suitable fluids depending on the process requirements. In someembodiments, the second liquid supply unit 320 is used to provide waterrinse during the thinning process. In some embodiments, the system 20may further include a nozzle 400 disposed aside the supplying assembly200 for providing a third liquid L3 from a different direction withrespect to the second discharging conduits 323 of the second liquidsupply unit 320. The third liquid L3 may be water, detergent, or othersuitable fluids for processing. In some embodiments, the third liquid L3discharges from the nozzle 400 may rinse away residuals (or anyremaining dusts) on the grinded surface of the first structure S1 tominimize the generation of contaminants. For example, the second liquidL2 flowing through the second discharging conduits 323 sprays obliquelydownward (as shown by arrow) to the front side FS of the first structureS1, and the third liquid L3 flowing through the nozzle 400 laterallysprays toward (as shown by arrow) the front side FS of the firststructure S1. A drying step is optionally performed followed by thethinning.

Since the edge EG of the first structure S1 is sealed with the firstliquid L1, vacuum leakage at the edge EG is eliminated, and theinterface IF between the first structure S1 and the carrying surface CSof the chuck 210 is remained at a vacuumed state, thereby facilitatingwarpage management. Due to the liquid seal LS at the edge EG of thefirst structure S1, the suction force may be uniform throughout thesucking portion 216 of the chuck 210 or may be distributed at a desiredcondition, thereby eliminating over-grinding concerns. The firststructure S1 can be firmly secured on the chuck 210 during the thinningprocess. After the first structure S1 is thinned, at least a portion ofthe conductive feature (e.g. conductive posts 112) of the firststructure S1 is exposed by the first insulating encapsulation 120 asshown in FIG. 1C. In some embodiments, after thinning the firststructure S1, the top surface 120 a of the first insulatingencapsulation 120 and the top surfaces 110 a of the first dies 110(shown in FIG. 1C) have planar topographies. For example, totalthickness variation (TTV) is a measure of surface uniformity. After thefirst structure S1 is thinned, a total thickness variation of thethinned surface at the front side FS of the first structure S1 mayachieve less than 1 μm. When the thinning process is completed, thethinned structure may be picked up and transported to the next stationfor subsequent processes.

According to some embodiments, a manufacturing method of thinning asubstrate is provided. The method includes at least the following steps.A liquid seal is provided at an interface between a chuck and asubstrate disposed on the chuck. The substrate is thinned during theliquid seal is provided.

According to some embodiments, a manufacturing method of thinning asemiconductor structure is provided. The method includes at least thefollowing steps. A semiconductor structure is formed, where thesemiconductor structure includes a first semiconductor die and a firstinsulating encapsulation encapsulating the first semiconductor die. Thesemiconductor structure is placed on a supporting assembly, where thesupporting assembly includes a chuck and a first liquid supply unitassembled on the chuck. A gap between the chuck and the semiconductorstructure is filled with a first liquid provided by the first liquidsupply unit. The semiconductor structure is thinned during the firstliquid is provided.

According to some embodiments, a system for thinning a substrateincludes a chuck including a carrying surface, and a first liquid supplyunit assembled on the chuck. The first liquid supply unit includes adischarging conduit obliquely disposed toward the chuck, where thedischarging conduit conveys a liquid flowing from at least one outlet ofthe discharging conduit towards the carrying surface of the chuck toseal an interface between the substrate and the carrying surface.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the disclosure.Those skilled in the art should appreciate that they may readily use thedisclosure as a basis for designing or modifying other processes andstructures for carrying out the same purposes and/or achieving the sameadvantages of the embodiments introduced herein. Those skilled in theart should also realize that such equivalent constructions do not departfrom the spirit and scope of the disclosure, and that they may makevarious changes, substitutions, and alterations herein without departingfrom the spirit and scope of the disclosure.

What is claimed is:
 1. A manufacturing method of thinning a substrate,comprising: providing a liquid seal at an interface between a top of achuck and a substrate disposed on the chuck, wherein a first liquidflows from a bottom of the chuck to the top of the chuck so as toprovide the liquid seal; and thinning the substrate during the liquidseal is provided.
 2. The manufacturing method according to claim 1,wherein providing the liquid seal comprises: laterally providing thefirst liquid to an edge of the substrate to seal a gap between the chuckand the substrate.
 3. The manufacturing method according to claim 1,further comprising: performing vacuum suction to the substrate throughthe chuck when the substrate is thinned.
 4. The manufacturing methodaccording to claim 1, further comprising: providing a second liquiddownwardly to the substrate when thinning the substrate.
 5. Themanufacturing method according to claim 1, further comprising:transferring the substrate to place on the chuck via a holding devicebefore providing the liquid seal; and releasing the substrate from theholding device before thinning the substrate.
 6. The manufacturingmethod according to claim 1, wherein the substrate comprises aninsulating encapsulation and a conductive feature covered by theinsulating encapsulation, and after the substrate is thinned, at least aportion of the conductive feature of the substrate is exposed by theinsulating encapsulation.
 7. A manufacturing method for thinning asemiconductor structure, comprising: forming a semiconductor structure,wherein the semiconductor structure comprises a first semiconductor dieand a first insulating encapsulation encapsulating the firstsemiconductor die; placing the semiconductor structure on a supportingassembly, wherein the supporting assembly comprises a chuck and a firstliquid supply unit laterally encircling the chuck; filling a gap betweenthe chuck and the semiconductor structure with a first liquid, whereinthe first liquid is delivered by the first liquid supply unit from abottom of the chuck to a top of the chuck; and thinning thesemiconductor structure during the first liquid is provided.
 8. Themanufacturing method according to claim 7, wherein when filling the gapbetween the chuck and the semiconductor structure, the first liquiddischarges from the first liquid supply unit and laterally flows to anedge of the semiconductor structure.
 9. The manufacturing methodaccording to claim 7, wherein the first liquid supply unit comprises aconduit obliquely disposed on the chuck, when the first liquid supplyunit provides the first liquid, the first liquid flows upwardly throughthe conduit and discharges to an edge of the semiconductor structure.10. The manufacturing method according to claim 7, wherein thesemiconductor structure is thinned via a thinning device, and thethinning device comprises a thinning wheel and a second liquid supplyunit surrounded by the thinning wheel, and the method further comprises:flowing a second liquid downwardly to the semiconductor structure viathe second liquid supply unit when the semiconductor structure isthinned.
 11. The manufacturing method according to claim 7, wherein thefirst semiconductor die of the semiconductor structure comprises aconductive feature covered by the first insulating encapsulation beforethinning, and after thinning the semiconductor structure, at least aportion of the conductive feature of the first semiconductor die isaccessibly revealed by the first insulating encapsulation.
 12. Themanufacturing method according to claim 7, wherein the semiconductorstructure further comprises a redistribution structure formed on thefirst semiconductor die and the first insulating encapsulation, a secondsemiconductor die disposed on the redistribution structure opposite tothe first semiconductor die, a conductive connector formed on theredistribution structure and aside the second semiconductor die, and asecond insulating encapsulation formed on the redistribution structureand encapsulating the second semiconductor die and the conductiveconnector, and after thinning the semiconductor structure, at least aportion of the conductive connector is accessibly revealed by the secondinsulating encapsulation.
 13. The manufacturing method according toclaim 12, wherein the second semiconductor die of the semiconductorstructure comprises a semiconductor substrate and a conductive via, theconductive via comprises one end embedded in the semiconductorsubstrate, and after thinning the semiconductor structure, at least aportion of the semiconductor substrate is removed, and the one end ofthe conductive via is accessibly revealed by the semiconductorsubstrate.
 14. A system for thinning a substrate, comprising: a chuckcomprising a carrying surface; and a first liquid supply unit laterallyencircling the chuck, and comprising: a discharging conduit obliquelydisposed toward the chuck, wherein the discharging conduit conveys aliquid flowing from a bottom of the chuck to a top of the chuck and theliquid discharges from at least one outlet of the discharging conduittowards the carrying surface of the chuck to seal an interface betweenthe substrate and the carrying surface.
 15. The system according toclaim 14, wherein a surface of the first liquid supply unit where the atleast one outlet of the discharging conduit is located is substantiallyleveled with the carrying surface of the chuck.
 16. The system accordingto claim 14, wherein the at least one outlet comprises a plurality ofopenings circumferentially distributed surrounding the carrying surfaceof the chuck.
 17. The system according to claim 14, wherein the chuckfurther comprises a frame portion comprising a recess, and a suckingportion disposed in the recess of the frame portion, the substrate isadapted to place on the sucking portion, and the first liquid supplyunit is engaged with the frame portion.
 18. The system according toclaim 14, further comprising: a liquid supply, disposed in a center ofthe chuck and being in communication with the discharging conduit. 19.The system according to claim 14, further comprising: a liquid supply,disposed in a periphery of the chuck and being in communication with thedischarging conduit.
 20. The system according to claim 14, furthercomprising: a thinning device disposed above the chuck, and comprising athinning wheel and a second liquid supply unit surrounded by thethinning wheel.